http://iscoresports.com/

At MLB games, I update rosters then manually enter a game (I do not use "discover" a game). I then sync both lineups. During the game, I may exit the scoring page , for example to check the player view or team view or data from a previous game. When I re-enter to continue scoring, most, sometimes all, of the rosters are doubled, or duplicated. And only one of the player names is associated with the stats from the game. I have to go to the lineup view and manually delete the duplicates.

How do I prevent duplicate rosters and lineups from being created mid-game?

We have not heard of this happening. If you can do an Options -> Export and email us your customer ID (found on Options screen) to support@iscoresports.com and let us know an example of a game with this issue, we can take a look at your data to see what is going on.